# US 8,569,031 B2 · Chemically modified carbonic anhydrases useful in carbon capture systems

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 8,569,031 B2
- Document ID: US8569031B2
- Status: Granted
- Kind: B2
- Application number: 13/721,648
- Filed: 2012-12-20
- Published: 2013-07-25
- Granted: 2013-10-29
- Earliest claimed: 2010-06-30
- Assignees: Codexis, Inc.
- Applicants: Codexis, Inc.
- Inventors: Scott J. Novick; Oscar Alvizo
- Web page: https://patentgrep.com/patent/US8569031B2

## CPC

- C12N 9/96: Stabilising an enzyme by forming an adduct or a composition; Forming enzyme conjugates
- B01D 53/1475: {Removing carbon dioxide}
- B01D 53/1493: {Selection of liquid materials for use as absorbents}
- B01D 53/84: Biological processes
- C12N 9/88: Lyases (4.)
- B01D 2252/20484: with one hydroxyl group
- B01D 2252/20489: with two or more hydroxyl groups
- B01D 2252/602: Activators, promoting agents, catalytic agents or enzymes
- B01D 2255/804: Enzymatic
- B01D 2257/504: Carbon dioxide
- B01D 2258/0283: Flue gases
- Y02C 20/40: of CO2
- Y02P 20/59: Biological synthesis; Biological purification
- C12N: MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA (microbiological testing media C12Q1/00)
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- Y02C: CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

The present disclosure relates to chemically modified carbonic anhydrase polypeptides and soluble compositions, homogenous liquid formulations comprising them. The chemically modified carbonic anhydrase polypeptides have improved properties relative to the same carbonic anhydrase polypeptide that is not chemically modified including the improved properties of increased activity and/or stability in the presence of amine compounds, ammonia, or carbonate ion. The present disclosure also provides methods of preparing the chemically modified polypeptides and methods of using the chemically modified polypeptides for accelerating the absorption of carbon dioxide from a gas stream into a solution as well as for the release of the absorbed carbon dioxide for further treatment and/or sequestering.

## Claims

### Claim 1

A method for removing carbon dioxide from a gas stream comprising the step of contacting the gas stream with a homogenous liquid solution under suitable conditions, wherein the solution comprises:
(i) an α-class carbonic anhydrase polypeptide chemically modified by treatment with a cross-linking agent; and
(ii) a CO2 absorption mediating compound;
whereby the solution absorbs carbon dioxide from the gas stream.

### Claim 2 (depends on 1)

The method of claim 1, wherein the chemically modified carbonic anhydrase has increased carbonic anhydrase activity in the presence of the CO2 absorption mediating compound relative to the activity of the same carbonic anhydrase polypeptide that is not chemically modified.

### Claim 3 (depends on 1)

The method of claim 1, wherein the chemically modified carbonic anhydrase has increased carbonic anhydrase activity in 4.2 M N-methyldiethanolamine (MDEA) at 50° C. compared to the activity under the same conditions of the same carbonic anhydrase polypeptide that is unmodified.

### Claim 4 (depends on 1)

The method of claim 1, wherein the cross-linking agent is selected from the group consisting of a dialdehyde, a bis-imidate ester, a bis(N-hydroxysuccinimide) ester, a diacid chloride, and mixtures thereof.

### Claim 5 (depends on 1)

The method of claim 1, wherein the cross-linking agent is a dialdehyde having one or more carbon atoms between the two aldehyde groups.

### Claim 6 (depends on 1)

The method of claim 1, wherein the cross-linking agent is a bis-imidate ester having one or more carbon atoms between the two imidate ester groups.

### Claim 7 (depends on 1)

The method of claim 1, wherein the cross-linking agent is a bis(N-hydroxysuccinimide) ester of a di-carboxylic acid.

### Claim 8 (depends on 1)

The method of claim 1, wherein the α-class carbonic anhydrase polypeptide is a recombinant carbonic anhydrase polypeptide derived from an α-class carbonic anhydrase comprising an amino acid sequence selected from the group consisting of SEQ ID NO: 1298, 1300, 1302, 1304, 1306, and 1308.

### Claim 9 (depends on 1)

The method of claim 1, wherein the CO2 absorption mediating compound is an amine compound selected from the group consisting of: 2-(2-aminoethylamino)ethanol (AEE), 2-amino-2-hydroxymethyl-1,3-propanediol (AHPD), 2-amino-2-methyl-1-propanol (AMP), diethanolamine (DEA), diisopropanolamine (DIPA), N-hydroxyethylpiperazine (HEP), N-methyldiethanolamine (MDEA), monoethanolamine (MEA), N-methylpiperazine (MP), piperazine, piperidine, 2-(2-tert-butylaminoethoxy)ethanol (TBEE), triethanolamine (TEA), triisopropanolamine TIA), tris, 2-(2-aminoethoxy)ethanol, 2-(2-tert-butylaminopropoxy)ethanol, 2-(2-tert-amylaminoethoxy)ethanol, 2-(2-isopropylaminopropoxy)ethanol, 2-(2-(1-methyl-1-ethylpropylamino)ethoxy)ethanol, and mixtures thereof.

### Claim 10 (depends on 1)

The method of claim 1, wherein the CO2 absorption mediating compound is MDEA and the suitable conditions comprise an MDEA concentration of at least 3 M and a solution temperature of from 40° C. to 110° C.

### Claim 11 (depends on 1)

The method of claim 1, wherein the CO2 absorption mediating compound is ammonia and the suitable conditions comprise an ammonia concentration of 1 M to 8 M and a solution temperature of from 0° C. to 20° C.

### Claim 12 (depends on 1)

The method of claim 1, wherein the CO2 absorption mediating compound is carbonate ion and the suitable conditions comprise from 0.1 M CO3−2 to 5 M CO3−2.

### Claim 13 (depends on 1)

The method of claim 1, wherein the method further comprises exposing the homogenous solution comprising the chemically modified carbonic anhydrase polypeptide, the CO2 absorption mediating compound, and absorbed carbon dioxide to suitable conditions for desorbing the carbon dioxide from the solution.

### Claim 14

A homogenous liquid formulation comprising an aqueous solution of a CO2 absorption mediating compound and a soluble composition having carbonic anhydrase activity comprising an α-class carbonic anhydrase polypeptide chemically modified by treatment with a cross-linking agent, wherein the chemically modified carbonic anhydrase has increased carbonic anhydrase activity in the presence of the CO2 absorption mediating compound relative to the activity of the same carbonic anhydrase polypeptide that is not chemically modified.

### Claim 15 (depends on 14)

The homogenous liquid formulation of claim 14, wherein cross-linking agent is selected from the group consisting of a dialdehyde, a bis-imidate ester, a bis(N-hydroxysuccinimide) ester, a diacid chloride, and mixtures thereof.

### Claim 16 (depends on 14)

The homogenous liquid formulation of claim 14, wherein the α-class carbonic anhydrase polypeptide is a recombinant carbonic anhydrase polypeptide having an activity half-life (t1/2) of at least 9 hours in 4 M MDEA at 50° C. prior to chemical modification and which is derived from an α-class carbonic anhydrase comprising an amino acid sequence selected from the group consisting of SEQ ID NO: 1298, 1300, 1302, 1304, 1306, and 1308.

### Claim 17 (depends on 14)

A method for removing carbon dioxide from a gas stream comprising the step of contacting the gas stream with a homogenous liquid formulation of claim 14 under suitable conditions, whereby the homogenous liquid formulation absorbs carbon dioxide from the gas stream.

### Claim 18

A method for preparing a chemically modified α-class carbonic anhydrase comprising contacting in a solution: (i) a recombinant carbonic anhydrase polypeptide derived from an α-class carbonic anhydrase comprising an amino acid sequence selected from the group consisting of SEQ ID NO: 1298, 1300, 1302, 1304, 1306, and 1308; and (ii) a cross-linking agent selected from the group consisting of a dialdehyde, a bis-imidate ester, a bis(N-hydroxysuccinimide) ester, a diacid chloride, and mixtures thereof.